The proteome of Toll-like receptor 3-stimulated human immortalized fibroblasts: implications for susceptibility to herpes simplex virus encephalitis.

J Allergy Clin Immunol. 2013 Apr;131(4):1157-66.

Pérez de Diego R, Mulvey C, Crawford M, Trotter MW, Lorenzo L, Sancho-Shimizu V, Abel L, Zhang SY, Casanova JL, Godovac-Zimmermann J.

Laboratory of Human Genetics of Infectious Diseases, Necker Branch, Necker Medical School, and Pediatric Hematology-Immunology Unit, Necker Hospital, Paris, France. rebeca.perez@idipaz.es

Abstract

BACKGROUND: Inborn errors in Toll-like receptor 3 (TLR3)-IFN type I and III pathways have been implicated in susceptibility to herpes simplex virus encephalitis (HSE) in children, but most patients studied do not carry mutations in any of the genes presently associated with HSE susceptibility. Moreover, many patients do not display any TLR3-IFN-related fibroblastic phenotype.

OBJECTIVE: To study other signaling pathways downstream of TLR3 and/or other independent pathways that may contribute to HSE susceptibility.

METHODS: We used the stable isotope labeling of amino acids in cell culture proteomics methodology to measure changes in the human immortalized fibroblast proteome after TLR3 activation.

RESULTS: Cells from healthy controls were compared with cells from a patient with a known genetic etiology of HSE (UNC-93B-/-) and also to cells from an HSE patient with an unknown gene defect. Consistent with known variation in susceptibility of individuals to viral infections, substantial variation in the response level of different healthy controls was observed, but common functional networks could be identified, including upregulation of superoxide dismutase 2. The 2 patients with HSE studied show clear differences in functional response networks when compared with healthy controls and also when compared with each other.

CONCLUSIONS: The present study delineates a number of novel proteins, TLR3-related pathways, and cellular phenotypes that may help elucidate the genetic basis of childhood HSE. Furthermore, our results reveal superoxide dismutase 2 as a potential therapeutic target for amelioration of the neurologic sequelae caused by HSE.

Copyright © 2013 American Academy of Allergy, Asthma & Immunology.

PMID: 23434283

 

Supplemental information

Investigating the herpes simplex encephalitis proteome.

Herpes simplex virus (HSV-1) encephalitis (HSE) is a devastating infection of the central nervous system. HSE is the most common form of sporadic viral encephalitis in Western countries, affecting approximately 1 in 250,000 individuals per year. It peaks in early childhood during primary infection with HSV-1. Treatment with acyclovir decreases the mortality rate in affected children, but significant neurological impairment is observed in most survivors. Childhood HSE has not been associable with known immunodeficiencies and its pathogenesis remained elusive until several genetic etiologies were identified. Inborn errors in the Toll like receptor 3-Interferon type I/III pathway have been implicated in susceptibility to childhood HSE. In this issue Perez de Diego et al focus their studies on patients which do not carry mutations in any of the presently known HSE-susceptibility causing genes. They use proteomics measurements by stable isotope labelling of amino acids in cell culture (SILAC) to measure changes in the human fibroblast proteome after TLR3 activation. As TLR3-dependent pathways are clearly involved in HSV-1 susceptibility, a combination of proteomics and systems biology methods have been used to study the involvement of additional protein networks. This study delineates a number of new targets, some of them with potential therapeutic, TLR3 related pathways and cellular phenotypes that may help elucidate the genetic basis of childhood HSE (see figure).

 

Illustration of the workflow followed in Perez de Diego et al.

Rebeca Perez-1

 

 

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